Let’s face it — Dexter, as a series, has been on a downslide since its apex in season four, with John Lithgow (hands-down Dexter’s best psychopathic foil) and Rita’s murder (arguably second only to Game of Thrones in terms of shocking character deaths in recent years). Season five introduced Lumen, Dexter’s rebound love interest and avenging-angel-in-training; I’m not sure whether fans were still loyal to Rita, or if the inexplicable anti–Julia Stiles backlash coupled with Lithgow withdrawal were too much to overcome, but that story arc fell flat. Last season began with promise — Edward James Olmos! Elaborate Biblical death scenes! — then fizzled out. Olmos and Colin Hanks were more campy than creepy, and the gimmick of whether Professor Gellar was alive or dead wore thin. This past summer, Dexter executive producer Sara Colleton explained that her intention was to end the series this season, but Showtime wrangled an eighth and final year. Sad as it is to see the show rounding the final turn toward the finish line, a (hopefully) definitive endpoint is welcome news for fans who’ve stuck around for a worthy denouement.

So last night’s episode was more than a season opener: It was really the beginning of an extended 24-episode finale. When we last saw Dexter, he’d just plunged a sword into the chest of Travis, the Doomsday Killer. The twist, of course, was that Deb saw him, too, and in doing so, hurled the show toward the inevitable moment when Dexter’s sister finally figures out her brother has killed approximately 72 people, give or take. While Breaking Bad has been charging toward an inexorable showdown between meth-mastermind Walt and his DEA-chief brother-in-law since its debut, Deb has been inching, slowly, toward this realization since she was a child. That’s something we saw again in flashbacks last night, as Harry forced Deb to give up her dog. It seemed extreme at first — hey, Pops, what say you add a “No puppies” clause to the Code?— but we, along with young Dexter, eventually learn the bigger lesson: Deb can never know his true nature. Harry’s rule makes sense. With their parents long gone, Deb is Dexter’s lifeline to the civilized world, perhaps the only person — including little Harrison, and clearly his stepkids — that Dexter feels connected to, emotionally. Cut that tether and he’d be alone, left with only his homicidal thoughts and a bag of knives.

Of course, with two more seasons to go and Deb’s notorious blind spot for her brother’s lifetime of weird behavior, we figured she still wouldn’t connect the dots right away. The episode begins with a clever bit of misdirection as Dexter hauls ass to the Miami airport and a pit stop for gas takes a harrowing turn when his credit cards are denied. Is he on the lam after Deb tried to turn him in? Is there a manhunt in progress? As it turns out, no and no. Dexter’s explanation for his ritual murder of Travis isn’t all that convincing (He “snapped”? No kidding! And don’t bring Rita into this, buster). As usual, Deb doesn’t see through the million holes in his Swiss cheese cover story, at least not at first. As the shock of what she witnessed — and of her complicity in the cover-up — wears off a bit, she begins asking questions. What about that apron and the gloves, Dex? The plastic wrap? The high-end cutlery? (Also, something no one asked at the crime scene — how could Travis skewer himself and then fall back on the table in a perfect pose, with arms to his sides?) Finally, after six seasons, Deb isn’t satisfied by her brother’s flimsy tales and deft dodges. The clincher is her flashback to a long-buried memory of being wrapped in plastic at the hands of the Ice Truck Killer, as Dexter told his brother Brian that he couldn’t kill her. The implication, she seems to realize, is that he’s perfectly fine with killing other folks.

The final scene is a jaw-dropper, as Dexter comes home to find Deb has turned his apartment upside down. On the table in front of her, we see the knives, the Ice Truck Killer hand, and the slides. As we’re waiting for Dexter to somehow wriggle his way out of this one, it’s time for some R. Kelly–style real talk:

Deb: Did you kill all these people?Dexter: I did.Deb: Are you … are you the serial killer?Dexter: Yes.

It’s one of the best scenes of the series to date, as we watch their lives unravel simultaneously in a matter of seconds. After his admission, Dexter closes his eyes, overwhelmed by both the liberation of revealing who he really is and the weight of the seismic ripple effects that will follow (among them: how Deb will reconcile her love for a guy who’s not only her stepbrother, but also apparently the most prolific murderer in American history). In a way, the episode felt like part two of a double cliff-hanger — first, what Deb saw in the church and still couldn’t believe, and now, what she discovered in Dexter’s apartment and the mind-melting truth that followed.

All of the other plotlines felt thin and somewhat predictable in comparison to that game-changing moment. Of course LaGuerta is causing trouble, palming the blood slide she found at the church for what could lead to the unraveling of the Bay Harbor Butcher case. Of course Quinn is still drinking. Of course he and Batista end up at a strip club. And of course, like Dexter’s nanny, the more we learn about Louis, the weirder he gets; as if Dexter doesn’t have enough problems, his stalker-groupie has a knack for hacking and canceled his credit cards. I’m not sure where the Ukrainian mob story line is headed, or what the deal is with the mystery man in Kiev — that scene felt like a moment from Chuck, which is oddly appropriate, since spybabe Yvonne Strahovski is onboard this season. But given Dexter’s admission to his homicide-lieutenant sister that he’s killed a crapload of people, the show now has what it’s been lacking since lovely Rita’s funeral: taut dramatic tension and the highest stakes. Whether that’s sustainable remains to be seen; unlike Breaking Bad and its final eight-episode sprint, Deb and Dexter have 23 more chapters before this story is over. But last night’s revelation suggests the end may be worth the wait.

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